Landing Page Dev't with Google Sheet and MailChimp Integration

We are an e-commerce business. Just to give you an idea of our plan we will include a scratch card insert in the package when we send out orders. Each insert will contain a unique code and a QR code that when scanned will direct the customer to the landing page. The customer will then input his details and the unique code. Each unique code will return a different outcome, depending on the code. Each detail entered by the customer on the form must be saved in the Google spreadsheet.

We would like to clarify a few details below before we proceed.

1. Lead time to integrate the backend for the Google Spreadsheet and can automate the subscribers with MailChimp. We can provide the XD file and the design itself
2. Lead time to develop the landing page using WordPress